Red Thread is a fungus disease that is a common turf problem in Western Washington. The disease develops most rapidly during periods of high moisture and cool temperatures (i.e. spring and fall). Lawns that are deficient in nitrogen are most susceptible to Red Thread. To help prevent Red Thread it is important to keep your lawn healthy by following a regular fertilization program.
We have no control over climatic factors (i.e. weather) but we can do something about cultural factors to help control Red Thread. Once you’ve determined that you have a Red Thread problem, there are several steps you can take to help cure the disease:
1) Increase nitrogen levels and apply lime
2) Apply an appropriate fungicide if necessary
Increase the nitrogen level in your lawn by using a quick release source of nitrogen such as 21-0-0 ammonium sulfate. Apply at a rate of 5 lbs. per 1000 sq. ft. and water in right away. This is important because if not watered in right away, the quick release nitrogen can burn your lawn. Apply lime to your lawn at a rate of 40 lbs. per 1000 sq. ft. By increasing the pH of the soil (sweetening the soil), the rate of organic matter decomposition by microorganisms increases. This makes the nitrogen and other nutrients more available to the turf. There are several types of lime. We would recommend applying either Dolopril or Dolomite lime. Dolopril is a quick acting granular form of lime whereas the Dolomite lime is finely ground, similar to sugar.
If Red Thread still persists in your lawn after applying 21-0-0 and lime, then you may need to apply an appropriate fungicide such as Fungaway, a granular fungicide. You will probably have to make two applications about 14 days apart. Follow the label directions carefully. Red Thread is easily spread by mowers, pets, walking on the lawn, etc. During periods of high disease infection, please keep activity on your lawn to a minimum. Keep your lawnmower clean and thoroughly wash after each mowing. It is also advised to sterilize the mower blades with an alcohol or chlorine solution.